January’s column was about snowflakes; this is about an ice cube, but a huge one called – wait for it – IceCube. Each side is 1 kilometer, 1,000 meters, so the volume is one billion cubic meters, and it weighs a billion tons. Scientists wanted a massive block of clear ice to detect mysterious neutrinos coming from far away in the universe. These particles interact with matter so rarely that 99.9999% pass right through that block leaving no trace. But one in a million hits a quark, much smaller than a proton, creating a shower of new particles, which make flashes of light in the ice.

Underneath the vast, frozen landscape of the South Pole lies IceCube, a gigantic observatory dedicated to finding ghostly subatomic particles called neutrinos. Neutrinos stream through Earth from all directions, but they are lightweight, abundant and hardly interact with their surroundings. A forthcoming upgrade to the IceCube detector will provide deeper insights into the elusive particles.

From Big Picture Science, Feb. 18, 2019: Fermilab scientist Anne Schukraft is interviewed in this podcast episode about ghostly particles called neutrinos — intriguing partly because they came decades before we had the means to prove their existence.

From The Washington Post, July 12, 2018: At the IceCube experiment at Earth’s South Pole, 5,160 sensors buried more than a mile beneath the ice detected a single ghostly neutrino as it interacted with an atom. Scientists then traced the particle back to the galaxy that created it.
The cosmic achievement is the first time scientists have detected a high-energy neutrino and been able to pinpoint where it came from.

For the first time, scientists have measured the rate at which high-energy neutrinos are absorbed by our planet, a development that could lead to discoveries about physics and Earth.